Industrial lift trucks

ABSTRACT

1,100,477. Masted lift trucks. LANSING BAGNALL Ltd. 31 May, 1966 [3 June, 1965], No. 23769/65. Heading B8H. In a masted lift truck, a reach carriage is movable along horizontal guides 22, 23, which are connected by a turntable mounting to a bracket on the lifting carriage, by a pair of driven endless chains 43 the arrangement being such that the connections between links 49, pivoted to the reach carriage, and the chains pass part of the way around the end sprockets at the limits of movement of the reach carriage whereby the speed of the carriage is reduced as it approaches the limits. In the embodiment shown, the reach carriage comprises a section 29, supporting the fork arms 32 and pivoted to the links 49, and a section 28 suspended from a trolley running in the guides 22, 23 and connected by a scissor linkage 33, 37, 38 to the section 29. The turntable mounting and the endless chains are driven by electric motors and limit switches are provided at the limits of travel of the endless chains. In a modification (not shown) the links 49 are pivoted to the section 28 of the reach carriage and hydraulic rams are provided to expand and contract the scissor linkage. In a further embodiment (not shown), the scissor linkage is replaced by a rigid link.

JulyZ, 1968 J. D. DIXON INDUSTRIAL LIFT TRUCKS 2 Sheets-Sheet 1 Filed June 1, 1966 July 2, 1968 J. o. DIXON INDUSTRIAL LIFT TRUCKS 2 Sheets-Sheet 2 Filed June 1, 1966 United States Patent 3,390,798 7 INDUSTRIAL LIFT TRUCKS John David Dixon, Basingstoke, England, assignor to Lansing Bagnall Limited, Basingstoke, England, a British company Filed June 1, 1966, Ser'.'No. 554,368

Claims priority, applicationgyggt Britain, June 3, 1965,

4 Claims. (Cl. 214-730) ABSTRACT OF THE DISCLOSURE An industrial lift truck has a load-lifting carriage, a reach carriage formed in two parts, one part being supported and guided for reach movement by the load-lifting carriage and the other part having load carrying means, which parts are connected together by a scissorslike coupling, and driving meanswhich are capable of both advancing and retracting the said part of the reach carriage which'is guided for 'reach movernent by the'loadlifting carriage and also of expanding and contracting the said coupling. Y

This invention relates to industrial lift trucks.

According to the invention an industrial lift truck is provided with a load-lifting carriage, a reach carriage connected to thelload-li fting carriage, guide means for the reach carriage, means for advancing and retracting the reach carriage along the guide means which advancing and retracting means comprise a driving member with a driving connection to the reach carriagewhich member moves (e.g. at a substantially constant. speed) along a path which is mainly parallel to. the direction'of movement of the reach carriage along the guide means and which path at one, or each en d thereof turns away from the parallel portion whereby the rate of movement of the member in said'direction is reduced when the member reaches said end and the rate of movement of the reach carriage is reduced. u I

In the preferred form of the invention, the truck is provided 'with an upstanding mast, a horizontally extending bracket constituting the load-lifting carriage which bracket is carried on the mast and from which depends the reach carriage, means for effecting relative movement between the mast and the bracket, and a turntable mechanism mounted on the bracket so as-to be able to effect rotation of the reach carriage,

It is also preferred that the reach carriage is formed in two parts connected together by a scissors-like coupling and that one of said parts is provided with load carrying means, the parts of the reach carriage being movable independently of each other by expansion or contraction of the said coupling. In this case the driving member is preferable in driving connection with the part of the reach carriage which is provided with the load carrying means.

The driving member may be a link.

In one form of the invention, the said advancing and retracting means comprise an endless chain or belt which passes around two pulleys or sprockets positioned at either end of the guide means for the reach carriage, which chain or belt carries the driving member. Preferably the driving member is capable of being directed a partway around one of the pulleys by the chain or belt to turn it away from the parallel portion of its path.

Stop means are preferably provided to stop the advancing and retracting means when the rate of movement of the driving member has been reduced by the required amount.

By way of example, one construction of truck in accordance with the invention will now be described with reference to the accompanying drawings in which:

FIGURE 1 is a front perspective view of the truck;

FIGURE 2 is a rear perspective view of the reach carriage of the truck shown in FIGURE 1; i

FIGURE 3 is an elevation, partly cut-away, of the means for advancing and retracting the reach carriage of the truck shown in FIGURES l and 2, the figure showing the two extreme positions of the driving member in driving connection between the said means and the reach carriage; and e FIGURE 4 is a plan view of the means shown in FIG- URE 3.

With referenceto the drawings, the truck comprises a heavy body 10 with two wheels 11 at the front corners on fixed axes and two steering and propelling wheels 12 at theback, and an appropriate driving mechanism 13 over the back wheels 12 with a space 14 between the steering and driving mechanism and the front end of the body 10. At the front end there is a fixed or outer mast 15 and on the outer mast there is a rising or inner mast 16. Running in this rising mast 16, there is a horizontal and forwardly projecting load lifting carriage or bracket 17. Each of the masts 15, 16 is formed of two upright guide members in parallel spaced-apart relation in known manner and the space between the two sides of the masts is unobstructed so that the forwardly projecting bracket 17 can run up and down freely. A jack 25 is provided for effecting this raising and lowering of the bracket 17 and of the inner mast 16, which jack 25 is provided behind the guide members of the outer mast 15, i.e. in the space 14 between the outer mast 15 and the driving mechanism 13 of the truck.

The bracket 17, which in its lowest position, is well spaced above the ground, has secured to its underside a turntable mounting 19. This turntable mounting 19 comprises a gear wheel mechanism and is driven by an electric motor 20 through a wormreduction gear 21. On either side of the turntable mounting and movable in fixed relation therewith, there are two channel-shaped guides 22, 23 disposed parallel to one another with their flanges facing outwardly. The guides extend in both directions from the turntable mounting 19 for a short distance and are made of as great a length as will clear the mast on rotation of the turntable mechanism, the length of the guides 22, 23 being determined by the .amount of overhang of the-bracket 17.

On the guide channels 22, 23 there is an underhung reach carriage 18, which carriage is formed in two parts 28, 29, the part 28 being provided with rollers 31 to run in the guide channels 22, 23. Stop means 24 are provided at each end of the guide channels. The other part 29 is provided with outwardly projecting load-carrying forks 32. Means are provided for attaching the two parts 29, 28 of the reach carriage together, which means comprise a pair of scissors-like couplings 34, 35 and a central lever 33, the couplings 34, 35 and the lever 33 being mounted on a transverse shaft 36. Each coupling (see FIGURE 2) comprises a first link 37 extending between the two parts 28, 29 and a second link 38 extending between the shaft 36 and the part 28. The upper ends of the links 37, 38 are provided with rollers 41 which engage in vertical guides 39, 40 respectively. By this arrangement, each part 28, 29 of the reach carriage may be moved independently of the other part by expansion or contraction of the couplings 34, 35. The provision of the guides 39, 40, also allows the couplings 34, 35 to expand or con tract without necessitating a corresponding amount of expansion or contraction of the two parts of the reach carriage.

The mechanisms for moving the reach carriage 18 comprises a pair of endless chains 43, 44 extending be- Patented July 2, 1968 the guide channels 22, 23, the sprockets 45 being driven by an electric motor 47 through a'reduction gear box 48.

Connecting one of the chains 43, 44 to the corresponding side of the part 29 of the reach carriage, there is a driving member 49 which, in'this example, is a rigid arcuate link designed to travel in fixed relation with the part 29 of the reach carriage and in a path parallel to that of the part 29 until the reach carriage approaches either its fully advanced position (shown in chain lines) or itsfully retracted position (shown in full lines). At either of these points the end of the link 49 which is attached to one of the endless chains 43, 44 will be located such that it will begin to pass around one of the sprockets 45, 46 i.e. follow the path of the chain which turns the link away from the path of the reach carriage. This effect will cause the rate of movement of the link 49 and hence the reach carriage in the direction of movement of the carriage to be reduced, which reduced rate of movement will be steadily increased until a stop mechanism operates to stop the motor 47 driving the chains 43, 44 and hence to stop the movement of the link 49. This stop mechanism comprises for each direction of traverse of the chains 43, 44, a horizontal projection 50 fixed to the respective chain and which is capable of deflecting a lever 51 against spring pressure thereby allowing the plunger 52 of a limit switch 53 to move longitudinally a sufficient extent to change the state of the switch. With reference to the drawings, the stop 50 on the chain 44 is located a short distance ahead of the link 49 and is operative at the position of the link which is associated Wtih the fully retracted position of the reach carriage. Also, the stop 50 on the chain 43 is located a further distance ahead of the corresponding link 49 and is operative at the position of the link which is associated with the fully advanced position of the reach carriage.

The motors 20 and 47 are controlled by hand levers rotated on top of the driving mechanism 13 within easy reach of the operator, so he can control the rotating and reaching movements of the reach carriage 18 at positions intermediate the limits of their movement.

In operation, movement of the chains 43, 44 in one direction or the other will by means of the links 49, effect movement of the part 29 of the reachcarriage which, in turn, will effect either subsequent or simultaneous movement of the part 28 of the reach carriage, the reduced rate of movement being eifected just before both the parts 28, 29 of the reach carriage reach their fully advanced or retracted positions.

I claim:

1. An industrial lift truck having a load-lifting carriage, a reach carriage connected to the load-lifting carriage, which reach carriage is formed in two parts, one part being supported by the load-lilting carriage and the other part having 105a carrying means, and which parts are connected together by a scissors-like coupling, the

ans of the reach carriage being movable independently of each other by expansion and contraction of the said coupling, guide means provided by the load-lifting carriage for guiding the reach movement of the said one part of the reach carriage, and driving means which are capable of both advancing and retracting the said one part of the reach carriage along the guide means and also of expanding and contracting the said coupling between the two parts of the reach carriage, which driving means comprise an endless member extending between and around two fixed points positioned one at either end of the said guide means for the said one part of the reach carriage and a driving link pivotally connected at one end to the said endless member and at its other end to the said other part of the reach carriage.

2. A truck as claimed in claim 1 in which the said endless meniber is anendless chain which passes between and around two sprockets positioned one at either end of the guide means for the'said one part of the reach carriage, the path of the chain between the sprockets being parallel to the direction of movement of the reach carriage,and in which the driving link is capable of being carried by the chain a part way around each of the sprockets whereby during said passage of the link around a part of each of the sprockets, the speed of the link in the direction of movement of the reach carriage, and hence the speed of the reach carriage, is reduced.

3. A truck as claimed in claim 2 in which stop means are provided to stop the said chain when the driving link has moved the required distance around the respective sprocket.

4. A truck as claimed in claim 1 in which the truck is provided with an upstanding mast, a horizontally extending bracket constituting the load-lifting carriage which bracket is carried on the mast and from which depends the said one part of the reach carriage, means for ef fecting relative movement of the bracket up and down the mast, and a turntable mechanism mounted on the bracket so as to be able to eflFect rotation of both parts of the reach carriage as a unit.

References Cited UNITED STATES PATENTS 2,652,162 9/1953 Auger 214-161 2,709,017 5/1955 Ulinski 214-730 3,190,473 6/1965 Loef 214-670 X 3,202,242 8/1965 Dolphin 21473O ROBERT G. SHERIDAN, Primary Examiner.

HUGO O. SCHULZ, Examiner.

R. BALLANTYNE, Assistant Examiner. 

